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authorMarkus Metzger <markus.t.metzger@intel.com>2020-03-13 09:58:10 +0100
committerMarkus Metzger <markus.t.metzger@intel.com>2020-04-21 15:54:32 +0200
commit5897fd4994effd21cbe951e6d2c417097adea162 (patch)
treeb32e41dedc31f20b4dc4a849b2b7a13b85ec84cd
parent1a476b6d68f338e6daa0345501c0cf0fe97dd8f3 (diff)
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gdb, btrace: diagnose double and failed enable
GDB silently ignores attempts to enable branch tracing on a thread that is already recorded. This shouldn't happen as recording is enabled exactly once: - when the btrace record target is opened for existing threads - when a new thread is added while the btrace record target is pushed GDB also silently ignores if recording is disabled on threads that were not recorded. This shouldn't happen, either, since when stopping recording, we only disable recording on threads that were recorded. GDB further silently ignores if recording was not enabled by the corresponding target method. Also this shouldn't happen since the target is supposed to already throw an error if recording cannot be enabled. This new error in btrace_enable catches cases where the target silently failed to enable recording. Throw an error in those cases. This allows us to detect an actual issue more easily. It will be addressed in the next patch. gdb/ChangeLog: 2020-03-19 Markus Metzger <markus.t.metzger@intel.com> * btrace.c (btrace_enable): Throw an error on double enables and when enabling recording fails. (btrace_disable): Throw an error if the thread is not recorded.
-rw-r--r--gdb/ChangeLog6
-rw-r--r--gdb/btrace.c10
2 files changed, 12 insertions, 4 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c761d49..0511000 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,11 @@
2020-04-21 Markus Metzger <markus.t.metzger@intel.com>
+ * btrace.c (btrace_enable): Throw an error on double enables and
+ when enabling recording fails.
+ (btrace_disable): Throw an error if the thread is not recorded.
+
+2020-04-21 Markus Metzger <markus.t.metzger@intel.com>
+
* record-btrace.c (record_btrace_target::fetch_registers): Forward
request if we do not have a thread_info.
diff --git a/gdb/btrace.c b/gdb/btrace.c
index 9f90d59..d41e3c4 100644
--- a/gdb/btrace.c
+++ b/gdb/btrace.c
@@ -1592,7 +1592,8 @@ void
btrace_enable (struct thread_info *tp, const struct btrace_config *conf)
{
if (tp->btrace.target != NULL)
- return;
+ error (_("Recording already enabled on thread %s (%s)."),
+ print_thread_id (tp), target_pid_to_str (tp->ptid).c_str ());
#if !defined (HAVE_LIBIPT)
if (conf->format == BTRACE_FORMAT_PT)
@@ -1604,9 +1605,9 @@ btrace_enable (struct thread_info *tp, const struct btrace_config *conf)
tp->btrace.target = target_enable_btrace (tp->ptid, conf);
- /* We're done if we failed to enable tracing. */
if (tp->btrace.target == NULL)
- return;
+ error (_("Failed to enable recording on thread %s (%s)."),
+ print_thread_id (tp), target_pid_to_str (tp->ptid).c_str ());
/* We need to undo the enable in case of errors. */
try
@@ -1651,7 +1652,8 @@ btrace_disable (struct thread_info *tp)
struct btrace_thread_info *btp = &tp->btrace;
if (btp->target == NULL)
- return;
+ error (_("Recording not enabled on thread %s (%s)."),
+ print_thread_id (tp), target_pid_to_str (tp->ptid).c_str ());
DEBUG ("disable thread %s (%s)", print_thread_id (tp),
target_pid_to_str (tp->ptid).c_str ());